9.—(1) Where there has been a voluntary payment, the Department may apply the amount of the voluntary payment to reduce any arrears of child support maintenance due under any previous maintenance calculation in respect of the same relevant persons.
(2) Where there is no previous maintenance calculation, or an amount of the voluntary payment remains after the application of paragraph (1), the Department may adjust the amount payable in relation to the current maintenance calculation by such amount as it considers appropriate in all the circumstances of the case, having regard in particular to—
(a)the circumstances of the relevant persons; and
(b)the amount of the voluntary payment and the period over which it would be reasonable to adjust the amount payable for the voluntary payment to be taken into account.
(3) An adjustment of the amount payable in relation to the current maintenance calculation under paragraph (2) may reduce the amount payable to nil.